9:30 AM - 9:45 AM
[AOS10-03] Dependence of the mechanisms associated with a potential multi-decadal AMOC-AMO-NAO feedback loop in MIROC model
Keywords:multi-decadal climate variability, air-sea interaction, North Atlantic, AMO, AMOC, NAO
Our preliminary results indicate that the updated version of the model, MIROC6, with a high-top and a shallow convection scheme, better simulates the tropical part of the AMO-associated SST pattern, which is commonly underrepresented in climate models. MIROC6 appears to be also better at simulating a coherent relationship among AMO, AMOC, and NAO within the model, with its lead-lag relationship of each link being consistent with the previous observational and modelling studies. Some of the previously suggested mechanisms linking each of these climate components in this multi-decadal feedback loop, however, seem to be associated with different time scales within MIROC6; in particular, the mechanisms linking the AMO and the opposite-signed NAO on the multi-decadal scale is likely linked with the shorter timescales in MIROC6, leaving the mechanisms associated with the multi-decadal relationship still unexplained. In this talk, we will illustrate differences in mechanisms associated with the multi-decadal and shorter timescales within the model and show that the conventional AMO definition computed with a low-pass filtering may lead to a convolution of processes associated with different timescales.